A team of researchers affixed heart tissue from a rat onto the body of the robot. When the tissue contracted, the robot's six horizontally aligned legs (see image) pulled together. When the tissue relaxed, the legs drew apart. The pulses propelled the robot forward through a solution at 100 micrometers per second (about 0.0002 mile per hour). The researchers hope to make other biocompatible devices that could one day carry clot-busting agents to clogged vessels.

A robot controlled by a simulated rat brain has proved itself to be a remarkable mimic of rodent behaviour in series of classic animal experiments. The robot's biologically-inspired control software uses a functional model of "place cells". These are neurons in an area of the brain called the hippocampus that help real rats to map their environment. They fire when an animal is in a familiar location.

Alfredo Weitzenfeld, a roboticist at the ITAM technical institute in Mexico City, carried out the work by reprogramming an AIBO robot dog, made by Japanese firm Sony, with the rat-inspired control software. When placed inside a maze, the robot learnt to navigate towards a "reward" in a remarkably similar way to real rodents, using landmarks to explore.

So in the year of the ratbot, look out for two things: robots controlled with pieces of rat bodies, and robots whose brains are modeled on those of our whiskery rodent friends. Yesterday's rat is tomorrow's robot!